All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
Your wife has the right over you that you do not stay away from her for more than six months except with her permission. This was the verdict of ‘Umar, may Allah be pleased with him. ‘Umar asked his daughter Hafsah how long a woman can endure being away from her husband, and she said, “Five or six months.” So he set a time limit of six months for the soldiers in military campaigns: they would march for a month, then stay there for four months, and then take another month for the journey back.
Muslim scholars underlined that if this period of time (six months) ends and the wife asks her husband to return, he is obliged to return unless he has a valid excuse that prevents him from returning.
The Hanbali scholar Al-Buhooti wrote, “If the husband travels and leaves her (his wife) because of an excuse or need, then her right to a share of his time and intimacy is waived, even if his journey is lengthy, because there is an excuse. If the traveler does not have an excuse that prevents him from returning and he is absent for more than six months, then if she asks him to return, he must do that.” [Kashshaaf Al-Qinaa’]
They also underlined that she is entitled to request a divorce if he refuses to return. Al-Mardaawi wrote, “The apparent indication of his statement is that if the wife requests his return after six months and he refuses to come back, then she is entitled to request the annulment of the marriage...” [Al-Insaaf]
Hence, you wife has a right over you to ask you to come back; however, she has no right to interfere in the matter of renewing your contract. If she agreed that you stay there longer, even if unwillingly, then there is no harm in staying there. However, our advice to you is to return to your wife in order to guard your chastity and hers, especially given that she is sick and suffering, as stated in the question.
It is better if your wife can live with you in the same place; meaning that it is better if you can bring her to live with you in the country where you work if you can. Allah, The Exalted, may facilitate your affairs because of that and bless you with great blessings and rewards beyond your imagination.
Allah knows best.